As a result of continuing technical progress, the processing and exchanging of electronic data has reached a high level. In order to provide new, more complex software programs, existing software programs may be used as components for a new software program. A Web service may be defined as a software program that is accessible via a communication infrastructure. The communication infrastructure may be, for example, the Internet or an intranet of an organization or a group of organizations. The communication infrastructure may allow for providing input data to a Web service and obtain output data from the Web service. In an example, a set of Web services may be used as an abstraction of a system interface of a company's information technology (IT).
A new Web service may be obtained by composing existing Web services. Composing existing Web services may include specifying an order in which different Web services are called and how data are exchanged between the different Web services.
Web services may be described in standard languages such as Web service description language (WSDL), semantic annotations for WSDL (SAWSDL), or Web service business process execution language (WSBPEL). A representation of a Web service may be defined as an object that allows for an identification of the Web service and that may be part of an environment that is different from the environment of the Web service. Therefore, a composition of representations of a group of Web services may be used to compose the Web services of the group.